1. Technical Field
The invention relates to user manual entry of text using a digital data processing device. More particularly, the invention relates to computer driven operations to supplement a user's inherently ambiguous, manual text entry with voice input to disambiguate between different possible interpretations of the user's text entry.
2. Description of Related Art
For many years, portable computers have been getting smaller and smaller. Tremendous growth in the wireless industry has produced reliable, convenient, and nearly commonplace mobile devices such as cell phones, personal digital assistants (PDAs), global positioning system (GPS) units, etc. To produce a truly usable portable computer, the principle size-limiting component has been the keyboard.
To input data on a portable computer without a standard keyboard, people have developed a number of solutions. One such approach has been to use keyboards with less keys (“reduced-key keyboard”). Some reduced keyboards have used a 3-by-4 array of keys, like the layout of a touch-tone telephone. Although beneficial from a size standpoint, reduced-key keyboards come with some problems. For instance, each key in the array of keys contains multiple characters. For example, the “2” key represents “a” and “b” and “c”. Accordingly, each user-entered sequence is inherently ambiguous because each keystroke can indicate one number or several different letters.
T9® text input technology is specifically aimed at providing word-level disambiguation for reduced keyboards such as telephone keypads. T9 Text Input technology is described in various U.S. Patent documents including U.S. Pat. No. 5,818,437. In the case of English and other alphabet-based words, a user employs T9 text input as follows:
When inputting a word, the user presses keys corresponding to the letters that make up that word, regardless of the fact that each key represents multiple letters. For example, to enter the letter “a,” the user enters the “2” key, regardless of the fact that the “2” key can also represent “b” and “c.” T9 text input technology resolves the intended word by determining all possible letter combinations indicated by the user's keystroke entries, and comparing these to a dictionary of known words to see which one(s) make sense.
Beyond the basic application, T9 Text Input has experienced a number of improvements. Moreover, T9 text input and similar products are also available on reduced keyboard devices for languages with ideographic rather than alphabetic characters, such as Chinese. Still, T9 text input might not always provide the perfect level of speed and ease of data entry required by every user.
As a completely different approach, some small devices employ a digitizing surface to receive users' handwriting. This approach permits users to write naturally, albeit in a small area as permitted by the size of the portable computer. Based upon the user's contact with the digitizing surface, handwriting recognition algorithms analyze the geometric characteristics of the user's entry to determine each character or word. Unfortunately, current handwriting recognition solutions have problems. For one, handwriting is generally slower than typing. Also, handwriting recognition accuracy is difficult to achieve with sufficient reliability. In addition, in cases where handwriting recognition algorithms require users to observe predefined character stroke patterns and orders, some users find this cumbersome to perform or difficult to learn.
A completely different approach for inputting data using small devices without a full-sized keyboard has been to use a touch-sensitive panel on which some type of keyboard overlay has been printed, or a touch-sensitive screen with a keyboard overlay displayed. The user employs a finger or a stylus to interact with the panel or display screen in the area associated with the desired key or letter. With a small overall size of such keyboards, the individual keys can be quite small. This can make it difficult for the average user to type accurately and quickly.
A number of built-in and add-on products offer word prediction for touch-screen and overlay keyboards. After the user carefully taps on the first letters of a word, the prediction system displays a list of the most likely complete words that start with those letters. If there are too many choices, however, the user has to keep typing until the desired word appears or the user finishes the word. Text entry is slowed rather than accelerated, however, by the user having to switch visual focus between the touch-screen keyboard and the list of word completions after every letter. Consequently, some users can find the touch-screen and overlay keyboards to be somewhat cumbersome or error-prone.
In view of the foregoing problems, and despite significant technical development in the area, users can still encounter difficulty or error when manually entering text on portable computers because of the inherent limitations of reduced-key keypads, handwriting digitizers, and touch-screen/overlay keyboards.